[G1 General] SolemnWishing:
October 22nd, 2008:

T-Mobile releases the exclusive HTC Dream or G1 as the first phone of the Open Handset Alliance using the Google Android operating system.

October 23rd, 2008:

Only one day after the release of the G1, T-Mobile releases an Over the Air update to update all handsets running on their 3G networks an update to provide better battery life and overall increase in performance. This update was known as RC-29, and is now the starting base for many new functions and hacks on XDA Developers

November 4th, 2008

Root access is discovered and gained through a bug in the RC-29 OTA update.

November 7th, 2008

T-Mobile releases their second update known as RC-30 to fix the root access bug in their previous update. Many OTA updates follow this, leading up to RC-33 early February.

November 22nd, 2008:

A person known by RyeBrye successfully modifies a kernel file on the G1, enabling a rough proof of concept of the G1's multitouch capabilities.

December 7th, 2008:

Stericson of XDA developers releases information on editing and flashing custom boot images onto the Dream.

December 15th, 2008:

Nandroid backup utility is released for the G1. This utility allowed users to backup and restore their phones to their original condition of which they were backed up from.

December 20th, 2008

XDA member Stericson develops the first theme for the Google Android platform which kicked off the rapid and quick development of many new themes. These new themes were flashed to the phone in the same way as firmware updates.

December 21st, 2008:

Members develop a version of firmware called "Cupcake". However, it is not the actual Cupcake or Android 1.5 update.

January 4th, 2009:

HardSPL, a modified version of the HTC bootloader now supporting fastboot commands is released.

Late January 2009:

XDA Developer member JesusFreke releases a working JF modified firmware.

February 4th, 2009:

T-Mobile releases the OTA Update known as RC-33, which included Google Latitude, Voice search and other features.

February 10th, 2009:

XDA Member JesusFreke releases his modified version of the RC-33 update, dubbed JF 1.42 along with ADP 1.1H.

February 11th, 2009:

Shortly after the release of JF 1.42, JF 1.43 is released to fix minor issues in the JF 1.42 version of the firmware.

February 26th, 2009:

The first 3G/Edge to Wi-Fi tether application for the G1 is released .

March 3rd, 2009:

The RC9 version of the JF 1.43 is released for UK users.

March 5th, 2009:

LucidREM, also a member of XDA developers releases a modified version of the JF firmware allowing support for moving system applications to the SD card.

March 26th, 2009:

XDA Member Haykuro successfully ports the HTC Magic/Sapphire firmware onto the G1, allowing the G1 to run Google Android version 1.5.

March 30th, 2009:

Version 0.9.6 of the G1 Wi-Fi tether program is released now supporting 128 bit WEP encryption and increased support to run on firmware with App2SD support.

April 13th, 2009:

Google releases Android SDK 1.5 pre for users to try out.

April 24th, 2009:

Haykuro successfully fixes all errors around G build of the Haykuro modified firmware not having access to the market.

This bit of a timeline has taken me a while, and I hope to continue to update it. Please let me know of any incorrect dates or important events I may have missed.